ST720r
FOR QUESTIONS, CALL 1-800-345-8746 in U.S. or
1-800-668-1238 in CANADA
www.TrimmerPlus.com
IMPORTANT MANUAL DO NOT THROW AWAY
Snow Thrower
OPERATOR'S MANUAL
ST720r
INTRODUCTION TABLE OF CONTENTS
2
THANK YOU
Thank you for buying this quality product. This modern
outdoor power tool will provide many hours of useful
service. You will find it to be a great labor-saving device.
This operator’s manual provides you with easy-tounderstand operating instructions. Read the whole
manual and follow all the instructions to keep your new
outdoor power tool in top operating condition.
PRODUCT REFERENCES, ILLUSTRATIONS,
AND SPECIFICATIONS
All information, illustrations, and specifications
in this manual are based on the latest product
information available at the time of printing. We reserve
the right to make changes at any time without notice.
Copyright© 2001 MTD SOUTHWEST INC
All Rights Reserved.
TrimmerPlus® is a registered trademark of
MTD SOUTHWEST INC
SERVICE INFORMATION
Service on this unit both within and after the warranty
period should be performed only by an authorized
and approved service dealer.
Dial:
1-800-345-8746 in the United States or
1-800-668-1238 in Canada
to obtain the listing of the authorized service dealer
nearest you.
DO NOT RETURN THE UNIT TO THE RETAILER.
NOTE: PROOF OF PURCHASE WILL BE
REQUIRED FOR WARRANTY SERVICE.
Make sure this manual is carefully read and understood
before starting or operating this equipment.
THIS PRODUCT IS COVERED BY ONE OR
MORE U.S. PATENTS.
OTHER PATENTS PENDING.
A complete parts list can be viewed and printed
by going to our web site, www.TrimmerPlus.com.
Or,
you can request a copy by calling1-800-345-TRIM
(1-800-345-8746). Please have the unit model and
serial number when calling.
I. Rules for Safe Operation . . . . . . . . . . . . . . . . . . . 3-6
A. Important Safety Information . . . . . . . . . . . . . 3-5
B. Safety and International Symbols . . . . . . . . . 5
C. Know Your Unit . . . . . . . . . . . . . . . . . . . . . . . 6
II. Operating Instructions . . . . . . . . . . . . . . . . . . . . . 7-8
A. Assembling the Coupler . . . . . . . . . . . . . . . . . 7
B. Special Cold Weather Starting Instructions . . 8
C. Operating the Snow Thrower . . . . . . . . . . . . . 8
D. Discharge Direction Adjustment . . . . . . . . . . 8
E. Tips for Best Snow Thrower Results . . . . . . . 8
III. Maintenance and Repair Instructions . . . . . . . . .9-11
A. Inspecting/Replacing the Drive Belt . . . . . . . 9
B. Replacing the Scraper . . . . . . . . . . . . . . . . . . 10
C. Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
D. Transporting . . . . . . . . . . . . . . . . . . . . . . . . . . 11
E. Accessories/Replacement Parts . . . . . . . . . . 11
IV. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
V. Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
CONTENTS OF CARTON
This unit should consist of the following:
• ST720r Snow Thrower Add-On
• Hanger
•Operator’s Manual
• Product Registration Card
NOTE: This product has been rated for use on both gas
and electric powerheads.
The purpose of safety symbols is to attract your
attention to possible dangers. The safety symbols,
and their explanations, deserve your careful attention
and understanding. The safety warnings do not, by
themselves, eliminate any danger. The instructions or
warnings they give are not substitutes for proper
accident prevention measures.
SYMBOL MEANING
SAFETY ALERT SYMBOL: Indicates
danger, warning, or caution. Attention is
required in order to avoid serious personal
injury. May be used in conjunction with
other symbols or pictographs.
NOTE: Advises you of information or instructions
vital to the operation or maintenance of
the equipment.
RULES FOR SAFE OPERATION
3
DANGER: Failure to obey a safety warning
will result in serious injury to yourself or to
others. Always follow the safety precautions
to reduce the risk of fire, electric shock, and
personal injury.
WARNING: Failure to obey a safety warning
can result in injury to yourself and others.
Always follow the safety precautions to
reduce the risk of fire, electric shock, and
personal injury.
CAUTION: Failure to obey a safety warning
may result in property damage or personal
injury to yourself or to others. Always follow
the safety precautions to reduce the risk of
fire, electric shock, and personal injury.
• IMPORTANT SAFETY INFORMATION •
• Do not operate the unit while under the influence of
drugs, alcohol, or medication.
• Inspect the unit before use. Replace damaged parts.
Make sure all fasteners are in place and secure. Replace
snow thrower parts that are cracked, chipped, or
damaged in any way. Make sure the snow throwing unit
is properly installed and securely fastened.
• Make sure the rotor will spin freely before attaching the
snow thrower to the powerhead.
• Dress properly. Wear adequate winter outer garments.
Wear heavy, long pants, boots, gloves and a long sleeve
shirt. Do not wear loose clothing, jewelry, short pants,
sandals or go barefoot. Secure hair above shoulder level.
• Wear footware that doesn't leak when operating the
snow thrower and that will improve footing on slippery
surfaces.
• Never attempt to make adjustments while the powerhead
is running (except when specifically recommended by
the manufacturer.)
• Let powerhead and machine adjust to outdoor
temperatures before starting to clear snow.
• Always wear safety glasses/shields or goggles at all
times during operation or while performing an adjustment
or repair to protect eyes from foreign objects that may be
thrown from the machine.
WHILE OPERATING:
• Stay away from the discharge opening at all times. Keep
face, hands, and feet away from concealed moving or
rotating parts.
• Be attentive when using the snow thrower, and stay alert
for holes in the terrain and other hidden hazards or traffic.
• Do not use on a gravel surface or crushed rock surfaces.
Use extreme caution when crossing gravel/crushed rock
drives, walks, or roads.
READ ALL INSTRUCTIONS
WARNING: When using the unit, the safety
rules must be followed. For your own safety
and that of bystanders, please read these
instructions before operating the unit. Please
keep the instructions safe for later use.
WARNING: To prevent electric shock, use only
with an extension cord suitable for outdoor use.
BEFORE OPERATING:
• Carefully read and understand the operator's manual of
the unit that powers this attachment.
• Read this operating instruction manual carefully. Be
thoroughly familiar with the controls and the proper use
of the equipment. Know how to stop the unit and
disengage the controls quickly.
• Never allow children to operate the equipment. Never
allow adults unfamiliar with the instructions to use the
unit. Never allow adults to operate the equipment without
proper instruction.
• Children and teens under the age of 15 must not use the
unit, except for teens guided by an adult.
• Keep bystanders, especially children and pets, at least
50 ft (15 m) away.
• Exercise caution to avoid slipping or falling, especially
when operating in reverse.
• Thoroughly inspect the area where the snow thrower is
to be used. Remove all doormats, sleds, boards, wires,
debris, and other foreign objects which may be thrown
by the snow thrower.
• Disengage all clutches and shift into neutral before
starting the powerhead.
RULES FOR SAFE OPERATION
4
• After striking a foreign object, turn the powerhead off
and inspect the snow thrower for damage. For gas
powerheads: Remove wire from the spark plug. For
electric powerheads: Disconnect the cord. Repair
damage before restarting and operating the unit.
• If the unit should start to vibrate abnormally, stop the
powerhead and check immediately for the cause.
Vibration is generally a warning of trouble.
• Stop the powerhead whenever you leave the operating
position, before unclogging the rotor or discharge
vanes, and when making any repairs, adjustments, or
inspections.
• Clear snow from slopes by going up and down. Never
go across the slope. Use caution when changing
directions. Never clear snow from steep slopes.
• Never attempt to use the snow thrower on a roof or
any steep, inclined, slippery surfaces.
• Never operate snow thrower without proper guards,
plates or other safety protective devices in place.
• Never operate the snow thrower near glass enclosures,
automobiles, trucks, window wells, dropoffs, etc.
without proper adjustment of the snow discharge
angle. Keep children and pets away.
• Don’t force or overload the snow thrower. Snow
thrower will perform at its best and safest when run at
the rate for which it was designed.
• Never operate the machine at high transport speeds on
slippery surfaces. Look behind and use care when
backing.
• Never direct discharge towards people or allow anyone in
front of the unit while operating.
•Disengage power to the rotor when snow thrower is
transported or not in use.
•Make sure the rotor will spin freely before attaching the
snow thrower to the powerhead.
• If the rotor will not rotate freely due to frozen ice, thaw
the unit thoroughly before attempting to operate it
under power.
•Keep the rotor clear of debris.
• Do not overreach. Keep proper footing and balance at
all times.
• Never discharge snow onto public roads or near
moving traffic.
• Let snow thrower run for a few minutes after clearing
snow so moving parts do not freeze.
• Never operate without good visibility or light. Always
be sure of your footing and keep a firm hold on the
handles. Walk; never run.
AFTER OPERATING:
• Follow instructions for care, maintenance, and storage
of snow thrower.
• Only qualified personnel should perform any repairs
or maintenance procedures that are not described
in this manual.
• Remove residue ice or snow from the vanes and rotor
by briefly running the unit out of snow.
• Store snow thrower indoors in a dry, locked place.
Keep out of the reach of children.
• Always refer to the operator's guide instructions for
important details if snow thrower is to be stored for an
extended period.
• Use only attachments and accessories approved by
the manufacturer of the snow thrower.
SPECIAL SAFETY WARNINGS FOR ELECTRIC
POWERHEADS AND SNOW THROWERS
•When cleaning, inspecting, or repairing, make certain
the rotor and all moving parts have stopped. Disconnect
the extension cord to prevent accidental starting.
• Use extension cords and receptacles as specified by
the manufacturer for all units with electric drive motors
or electric starting motors.
• Use only 3-wire outdoor extension cords that have 3prong grounding-type plugs and 3-pole receptacles
that accept the snow thrower's plug. Replace or repair
damaged cords.
• Do not abuse extension cord. Never carry snow
thrower by the cord or yank on the cord to disconnect
it from the receptacle.
• Keep the extension cord away from heat, oil, and sharp
edges to prevent damage.
• If extension cord is damaged in any manner while
plugged in, pull extension cord from receptacle.
• Prevent disconnection of snow thrower powerhead
from extension cord during operation by using a plugreceptacle retaining strap, connector, or by making a
knot as shown below:
• Do not use in rain or during a snowfall. Do not use in or
around water.
• Avoid accidental starting. Don't carry plugged-in snow
thrower with finger on switch.
Extension
Cord
Snow
Thrower Cord
Snow
Thrower Cord
Extension
Cord
RULES FOR SAFE OPERATION
5
SAFETY AND INTERNATIONAL SYMBOLS
This operator's manual describes safety and international symbols and pictographs that may appear on this product.
Read the operator's manual for complete safety, assembly, operating, maintenance and repair information.
SYMBOL MEANING
• SAFETY ALERT SYMBOL
Indicates danger, warning, or caution. May be used in conjunction with other
symbols or pictographs.
•WARNING - READ OPERATOR'S MANUAL
Read the Operator’s Manual(s) and follow all warnings and safety instructions.
Failure to do so can result in serious injury to the operator and/or bystanders.
• WEAR EYE AND HEARING PROTECTION
WARNING: The operation of any power tool can be the source of thrown objects
and loud noise which can cause severe eye injury and hearing loss. Always wear
safety glasses or goggles eye protection meeting ANSI Z87.1 standards and ear
protection when operating this unit. Use a full face shield when needed.
• KEEP BYSTANDERS AWAY
WARNING: Keep all bystanders, especially children and pets, at least 50 feet
(15 m) from the operating area.
• SPINNING ROTOR CAN CAUSE SEVERE INJURY.
WARNING:
Keep hands, feet, and clothing away from the discharge area. Do
not step in front of the unit, or use hands to clean the rotor area.
• THROWN OBJECTS CAN CAUSE SEVERE INJURY.
WARNING:
Small objects can be propelled at high speed, causing injury.
• Always unplug the unit and allow it to cool before
putting it into storage. Store indoors.
• Always unplug the unit when not in use, and before
performing any maintenance or repairs.
SPECIAL SAFETY WARNINGS FOR GAS
POWERHEADS AND SNOW THROWERS
•When cleaning, inspecting, or repairing, make certain
the rotor and all moving parts have stopped.
Disconnect the spark plug wire and keep the wire away
from the plug to prevent accidental starting.
• Handle fuel with care; it is highly flammable.
• Use an approved fuel container for mixing fuel. Avoid
spilling the fuel when mixing with the oil.
• Fill fuel tank of the power unit with extreme care in a
well-ventilated, area outdoors. Never fill fuel tank
indoors. Do not smoke while fueling the power unit.
• Never add fuel to a running engine or hot engine.
• After filling fuel tank, replace gasoline cap securely and
wipe up any spilled fuel. Move away from the fueling
area before starting the unit.
• Do not run the engine indoors, except when starting
the engine and for transporting the snow thrower in or
out of the building. Open the outside doors; exhaust
fumes are dangerous.
• Do not smoke while operating the unit.
• Refuel and store in an area free of potential fuel vapor
ignition sources such as open flames (pilot lights) or
electrical sparking devices (switches, electric motors).
• Turn off the engine and let it cool before refueling or
before putting the unit in storage.
SAVE THESE INSTRUCTIONS
RULES FOR SAFE OPERATION
6
KNOW YOUR UNIT
APPLICATIONS
As a Snow Thrower:
• Clears snow from walkways, driveways, sidewalks,
pathways, etc.
Discharge
Directional
Control
Vanes
Rotor
Flange Lock Nut
Cover Screws (7)
Belt Case Cover
Scraper
3. Turn the knob clockwise to tighten (Fig. 3).
CAUTION: Lock the release button in the
primary hole (Fig. 2) and securely tighten the
knob before operating this unit.
ASSEMBLING THE COUPLER
The TrimmerPlus® system enables the use of these
optional add-ons.
Blower/Vacuum . . . . . . . . . . . . . . . . . . . . . . . . . . BV720r
Cultivator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GC720r
Edger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LE720r
Hedge Trimmer . . . . . . . . . . . . . . . . . . . . . . . . . . . HS720r
Straight Shaft Trimmer . . . . . . . . . . . . . . . . . . . . . SS725r
Sweeper/Blower . . . . . . . . . . . . . . . . . . . . . . . . . . SB720r
Tree Pruner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TP720r
Turbo Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . TB720r
WARNING: Read and understand operator’s
manual for add-on prior to operation.
Removing the add-on:
1. Turn the knob counterclockwise to loosen (Fig. 1).
2. Press and hold the release button (Fig. 1).
3. While firmly holding the upper shaft housing, pull the
snow thrower attachment out of the coupler (Fig. 2).
Installing the add-on:
WARNING: To avoid serious personal injury
and damage to the unit, shut unit off before
removing or installing add-ons.
NOTE: To make installing or removing the add-on
easier, place the unit on the ground or on a
work bench.
1. Turn knob counterclockwise to loosen (Fig. 1).
OPERATING INSTRUCTIONS
7
CAUTION: The snow thrower attachment
with the coupler system is to be used in the
primary hole only. Using the wrong hole
could lead to personal injury or damage to
the unit.
Fig. 1
Coupler
Release Button
Guide Recess
Knob
Primary Hole
Upper Shaft
Housing
Coupler
2. While firmly holding the add-on, push it straight into
the coupler (Fig. 2).
NOTE: Aligning the release button with the guide recess
will help installation (Fig. 1).
Fig. 2
Fig. 3
Knob
Lower Shaft
Housing
Release Button
Knob
ClockwiseCounterclockwise
OPERATING INSTRUCTIONS
8
OPERATING THE SNOW THROWER
1. Squeeze the power trigger on the powerhead
to start the rotor. The depth and weight of the snow
governs the forward speed. Refer to the operator's
manual of the powerhead for further instructions.
2. Do not tip the snow thrower to self-propel. Push the
snow thrower so that unit rides on the scraper.
DISCHARGE DIRECTION ADJUSTMENT
Snow may be discharged to the left, straight forward, or
to the right.
To change the direction, use the following instructions:
1. Firmly grasp handle of discharge directional control and
pull up. This releases the rod, which is spring-loaded,
from the current discharge direction slot and allows free
movement (Fig. 4).
SPECIAL COLD WEATHER
STARTING INSTRUCTIONS
WARNING: To aid starting the two-cycle or
four-cycle gasoline powerheads in cold
weather, the unit should be stored in an area
with the temperature above 40˚F (4.4˚ C).
Refuel and store the gasoline powerhead in
an area free of potential vapor ignition sources
such as open flames (pilot lights) or electrical
sparking devices (switches, electric motors).
2 Turn the discharge directional control to the left,
center, or right, depending on which direction you
want to throw the snow (Fig. 5).
NOTE: From the center position, the discharge
directional control turns 45 degrees only in either
direction (left or right). Do not force.
3. Release discharge directional control into the
discharge direction slot to secure position of snow
throwing desired.
NOTE: Make sure discharge directional control is securely
positioned in direction slot and cannot rotate freely.
TIPS FOR BEST SNOW THROWER RESULTS
4. For the most efficient snow throwing, keep the vanes
parallel, throw snow downwind, and slightly overlap
each swath (Fig. 6)
5. Hold the unit by the handle and use a swinging or
sweeping motion when cleaning steps or deep drifts.
Fig. 4
Fig. 5
Fig. 6
45°45°
Discharge snow to
LEFT of operator
Discharge snow to
RIGHT of operator
Discharge snow in
FRONT of operator
View of snow thrower top
looking down on discharge directional control
Pull the discharge
directional control up
MAINTENANCE AND REPAIR INSTRUCTIONS
9
3. Pull the belt tensioner (idler arm) away from the drive
pulley. Remove the damaged or broken belt from the
driven pulley and drive pulley inside of the housing
(Fig. 8).
4. Loop the new belt around the drive pulley and driven
pulley (Fig. 8). Pull the belt tensioner (idler arm) away
from the drive pulley to install the belt around the
drive pulley.
NOTE: Make sure the washer is still in place on the
driven pulley shaft prior to reinstalling the belt
case cover (Fig. 8).
Drive Pulley
Cover
Screws (7)
Belt
Driven
Pulley
Flange Lock Nut
Belt Tensioner
(Idler Arm)
Fig. 7
Fig. 8
Belt Cover
Case
Washer
INSPECTING/REPLACING THE DRIVE BELT
When servicing the snow thrower use only original MTD
replacement parts. Inspect the drive belt once a year or
every 50 hours of operation, whichever comes first, for
wear. If the drive belt needs to be replaced, use the
following instructions.
1. Remove the flange lock nut from the belt case cover
with a wrench or nut driver (Fig. 7).
2. Remove the seven (7) screws from the belt case
cover using a #T20 Torx bit or flat blade screwdriver
(Fig. 7).
5. Reinstall the cover with the seven (7) screws. To
make installation easier, place the narrow part of the
cover into the recess of the housing. Install the top
two screws, then push the rest of the cover down
into the recess and over the rotor shaft. Torque all
seven (7) screws to 18-23 in•lb (2.0-2.5 N•m).
6. Install the flange lock nut. Torque the nut to 80-100
in•lb (9.0-11.2 N•m).
NOTE: If the flange lock nut is damaged, do not replace
it with a standard nut. Replace only with an
original MTD replacement part.
MAINTENANCE AND REPAIR INSTRUCTIONS
10
REPLACING THE SCRAPER
Use only original MTD replacement parts.
1. Place snow thrower on the ground or on work bench.
Position unit so vanes and rotor are facing up (Fig. 9).
2. Beneath the rotor, locate and remove the three (3)
screws securing the scraper to the housing using a
#T20 Torx bit or flat blade screwdriver (Fig. 9).
3. Remove the scraper and discard appropriately.
4. Reinstall the three (3) screws to secure new scraper
to the unit. Torque the screws to 25-30 in•lb
(2.8-3.3 N•m).
Scraper
Fig. 9
MAINTENANCE AND REPAIR INSTRUCTIONS
11
SNOW THROWER ADD-ON
Unit Weight (Add-On only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 lbs. (4.17 kg)
Snow Depth (maximum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-inches (.152 meters)
Cleared Path Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-inches (.305 meters)
STORAGE
• Check unit before storage to be sure the equipment is
in safe working condition.
• Remove the residue ice or snow from the rotor by
briefly running the unit out of the snow.
• Stop the engine or motor.
• Store the snow thrower indoors, in a dry and locked
place, out of the reach of children.
• Maintain or replace safety and instruction labels, as
necessary.
For gas powerhead units:
• Allow the unit to cool before storing in any enclosure.
• Drain fuel from unit. Never store the unit with fuel in the
fuel tank inside a building where ignition sources are
present such as hot water and space heaters, clothes
dryers, etc.
TRANSPORTING
• Allow the unit to cool before transporting.
• Secure the unit while transporting.
For gas powerhead units:
• Drain fuel from unit.
• Tighten fuel cap before transporting.
SPECIFICATIONS
ACCESSORIES/REPLACEMENT PARTS
Shoulder Strap . . . . . . . . . . . . . . . . . . . . . . . . . . .682075
Scraper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .731-2557
Drive Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .754-0633
Flange Lock Nut . . . . . . . . . . . . . . . . . . . . . . . .712-3004A
Use only original MTD replacement parts.
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